1. Field of the Invention
The present invention relates to a vapor phase deposition apparatus and a support table. For example, the present invention relates to a support member (support table) which supports a substrate such as a silicon wafer in an epitaxial growth apparatus.
2. Related Art
In manufacture of semiconductor devices such as an ultrahigh-speed bipolar transistor and an ultrahigh-speed CMOS, a monocrystalline epitaxial growth technique in which an impurity concentration and a film thickness are controlled is absolutely necessary to improve the performance of devices. In epitaxial growth for vapor-growing a monocrystalline thin film on a semiconductor substrate such as a silicon wafer, an atmospheric chemical vapor deposition method is generally used. Depending on cases, a low-pressure chemical vapor deposition (LP-CVD) method is used. A semiconductor substrate such as a silicon wafer is arranged in a reaction chamber. The semiconductor substrate is heated and rotated while keeping a normal-pressure atmosphere (0.1 MPa (760 Torr)) or a vacuum atmosphere having a predetermined degree of vacuum in the reaction chamber. In this state, a silicon source and a source gas containing a dopant such as a boric compound, an arsenic compound, or a phosphorus compound are supplied. On the surface of the heated semiconductor substrate, thermal decomposition or hydrogen reduction reaction of the source gas is performed. In this manner, a silicon epitaxial film doped with boron (B), phosphorous (P), or arsenic (As) is manufactured by deposition (see Japanese Patent Application, Publication No. JP-A-09-194296, for example).
The epitaxial growth technique is also used in manufacture of a power semiconductor, for example, manufacture of an IGBT (Insulate Gate Bipolar Transistor). In the power semiconductor such as the IGBT, a silicon epitaxial film having a thickness of several 10 μm or more is required.
FIG. 25 is a top view showing an example of a state in which a silicon wafer is supported by a holder.
FIG. 26 is a sectional view showing a section in a state in which the silicon wafer is supported by the holder shown in FIG. 25.
In a holder 210 (also called a susceptor) serving as a support member for the silicon wafer 200, a counterbore hole having a diameter slightly larger than the diameter of the silicon wafer 200 is formed. The silicon wafer 200 may be placed to be fitted in the counterbore hole. In this state, the holder 210 is rotated to rotate the silicon wafer 200, so that a silicon epitaxial film is grown by thermal decomposition or hydrogen reduction reaction of a source gas supplied.
In order to uniformly grow a silicon epitaxial film on the substrate, the substrate is heated as described above, and heat escapes through an edge portion of the substrate. For this reason, in particular, the uniformity of the film thickness of the substrate at an edge portion is disadvantageously deteriorated. For this reason, although the support member is devised to be heated, further improvement is desired.